The first rains in centuries in the Atacama Desert devastate its microbial life

The Atacama Desert, the driest and oldest desert on Earth, located in northern Chile, hides a hyper-arid core in which no rain has been recorded during the past 500 years. But this situation has changed in the last three years. For the first time, rainfall has been documented in the hyper-arid core of the Atacama, and contrary to what was expected, the water supply has caused a great devastation among local life. This is the main conclusion of an international study, published today in Scientific Reports titled "Unprecedented rains decimate surface microbial communities in the hyperarid core of the Atacama Desert," directed by researchers from the Center for Astrobiology (CAB). These recent rains are attributed to changing climate over the Pacific Ocean.

"Our group has discovered that, contrary to what could be expected intuitively, the never-before-seen rainfall has not triggered a flowering of life in Atacama, but instead, the rains have caused enormous devastation in the microbial species that inhabited the region before the heavy precipitations," explains Dr. Alberto G. Fairén.

Work - Rainfall - Extinction - Species - Extinction

"Our work shows that high rainfall has caused the massive extinction of most indigenous microbial species. The extinction range reaches 85 percent, as a result of the osmotic stress that has caused the sudden abundance of water: The autochthonous microorganisms, which were perfectly adapted to thrive under conditions of extreme dryness and had strategies optimized for the extraction of the scarce humidity of their environment, have been unable to adapt to the new conditions of sudden flooding and have died from excess water," adds Fairén.

This study represents a great advance to understanding the microbiology of extremely arid environments. It also presents a new paradigm to decode the evolutionary path of a hypothetical early microbiota of Mars, since Mars is a hyper-arid planet that experienced catastrophic floods in ancient times.